08盒模型之margin.html

<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>Document</title>
<style type="text/css">
div {
width: 200px;
height: 200px;
background-color: pink;
padding: 4px;
/* margin: 20px; */
/* margin-top: 10px;
margin-right: 20px;
margin-bottom: 30px;
margin-left: 40px; */
margin: 20px auto; /*左右auto 这样可以让块级带有宽度的盒子水平居中对齐*/
}
span {
margin: 0 auto; /*无效 因为span是行内元素*/
}
header {
margin: 0 auto; /*无效 因为没设置宽度*/
width: 400px;
}
</style>
</head>
<body>
<div></div>
<header>头部</header>
<span>span</span>
</body>
</html>
来源:https://www.cnblogs.com/HiJackykun/p/11048277.html